1. Field of the Invention
This invention relates to a plasma treatment apparatus for forming a film on the surface of a substrate by vapor deposition.
2. Description of the Related Art
Currently, film formation using a plasma CVD (chemical vapor deposition) system is known for production of a semiconductor. The plasma CVD system is a system in which a source gas for constituting a film is introduced into a film formation chamber within a container, high frequency waves are shot from a high frequency antenna to convert the source gas into the state of a plasma, and excited active atoms in the plasma promote chemical reactions on the surface of the substrate to carry out film formation.
In the plasma CVD system, an auxiliary gas and a cleaning gas for performing cleaning are introduced, along with the source gas which will become the material for the film. Thus, pipings for introducing a plurality of gases are connected to the container. A plurality of gas nozzles are provided in the circumferential direction of the container which is cylindrical in shape.
In the conventional plasma CVD system, the plurality of gas nozzles are provided in the container such that plural types of gas nozzles for the different types of gases are present, and plural gas nozzles of each type are present. To avoid mixing of the different gases, therefore, the same number of the pipings as the number of the gas nozzles are connected for each of the types of the gases. As a result, the piping system is complicated, making the configuration of the container complicated, eventually making the manufacture and disassembly of the container difficult.
To prevent gas leakage, etc. under these circumstances, much labor and a plenty of time have been required in inspecting the weld zone of the piping or testing for connection of the piping system. Depending on individual differences of the pipings, the gas flow rate or the pressure loss differs, and may cause imbalances in the amounts of the gases supplied.